[video_player] Fixes a bug where the aspect ratio of some HLS videos are incorrectly inverted

[hellohuanlin]

The issue is that item.presentationSize returns the swapped width and height for some video streams (likely due to transform).

I did lots of research and wasn't able to find any workaround online. Then I thought that each segment of the HLS may have different resolution (e.g. different internet speed), so AVFoundation must be adjusting the presentationSize continuously. Fixing aspect ratio could also be part of that adjustment. So I used the same trick as the previous PR to leverage AVPlayerLayer to do the heavy lifting work for us.

Just like the previous PR, we can also leverage AVPlayerLayer to do the heavy lifting work for us. And it worked :)

(If it weren't for the previous iOS 16 bug, I probably wouldn't be able to come up with this solution).

About the deprecated keyWindow.rootViewController

I simply copied the code from another plugin. Fixing it is not the scope of this PR (tho I'm happy to help if needed).

List which issues are fixed by this PR. You must list at least one issue.
Fixes flutter/flutter#109116

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[hellohuanlin]

I simply copied the code from another plugin. Fixing it is not the scope of this PR (tho I'm happy to help if needed).

[jmagman]

I think this needs a test to validate the presentationSize is correct, if that's possible to check.

[jmagman]

Rename test.

[jmagman]

I don't think we need this comment twice.

Suggested change

	// This is to fix 2 bugs: 1. blank video for encrypted video streams on iOS 16
	// (https://github.com/flutter/flutter/issues/111457) and 2. swapped width and height for some video
	// streams (not just iOS 16). (https://github.com/flutter/flutter/issues/109116).
	// An invisible AVPlayerLayer is used to overwrite the protection of pixel buffers in those streams
	// for issue #1, and restore the correct width and height for issue #2.

[hellohuanlin]

It turned out that validating presentationSize is trickier than i thought - it takes setting up pretty much the whole plugin, rather than just a few units. On the other hand, integration tests can probably provide good confidence too, but also stuck with the flakiness in previous PR.

I plan to dig deeper, but given the P2 priority, let's land it for now and revisit afterwards? WDYT? @jmagman

[jmagman]

On the other hand, integration tests can probably provide good confidence too, but also stuck with the flakiness in previous PR.

Checking the frames seemed flaky. I wouldn't have thought checking the width and height of the view would be flaky, since our tests that check the closed captioning isn't flaky. How were you testing it?

[hellohuanlin]

@jmagman I was referring to the flakiness of the integration test for the iOS 16 bug (previous PR), which is tracked here: flutter/flutter#112562

For this particular one, I am thinking about taking a screenshot and then scanning through pixels to determine the frame of the video area. (if i understand it correctly, since we are not using platform view, the video frames are simply drawn on the full-screen UIView just like any other widgets)

[hellohuanlin]

@jmagman Oh to clarify, I haven't tried out integration tests for this one. I was worrying it's taking longer time since it's P2. But if time permits, I can try integration test before Landing it.

[jmagman]

it's taking longer time since it's P2

We shouldn't land anything without proper tests, even P2s 🙂

@jmagman I was referring to the flakiness of the integration test for the iOS 16 bug (previous PR), which is tracked here: flutter/flutter#112562

That's what I'm referring to as well.

For this particular one, I am thinking about taking a screenshot and then scanning through pixels to determine the frame of the video area. (if i understand it correctly, since we are not using platform view, the video frames are simply drawn on the full-screen UIView just like any other widgets)

Scanning through pixels and taking screenshots was what was extremely flaky. I'm suggesting something more simple to just check the width and height of the video.

For example, using the video from the issue (note we shouldn't use that video, we should have our own that reproduces, though I wasn't able to get any of our test videos to repro), this fails on master on an iOS 14 simulator, but passes on this PR:

    testWidgets('m3u8 has correct aspect ratio', (WidgetTester tester) async {
      final MiniController livestreamController = MiniController.network(
        'https://videodelivery.net/11a75f7cf7314f5a880d49fb8bebaaed/manifest/video.m3u8',
      );
      await livestreamController.initialize();

      expect(livestreamController.value.isInitialized, true);
      expect(livestreamController.value.size.width, lessThan(livestreamController.value.size.height));
    });

to be added around here:

plugins/packages/video_player/video_player_avfoundation/example/integration_test/video_player_test.dart

Line 168 in b82bb69

testWidgets('live stream duration != 0', (WidgetTester tester) async {

[hellohuanlin]

@jmagman Ah I didn't realize we have tests on the dart side! Was thinking about xcuitests. Let me try tomorrow.

[hellohuanlin]

For the integration test, I wasn't able to create a video that reproduces the bug (more details here).

I created an issue to track it.

[jmagman]

LGTM